Research On Force Control Technology Of Minimally Invasive Surgical Robot

Since the 21st century,robotics has made breakthroughs in navigation,positioning,motion planning,intelligent recognition and remote control,and has been widely used in minimally invasive surgical robot systems.At present,Da Vinci and Zeus surgical robot systems are mainly used in minimally invasive surgical robot systems for clinical surgery.The application of surgical robot not only avoids the technical defects of natural hand tremor,large wound,poor stability and low precision in traditional surgical operation,but also has the advantages of low pain sensation,short recovery time and high flexibility,which greatly improves the success rate of surgery and has epochal significance in the medical field.However,there are still some key technical defects in minimally invasive surgery,that is,the surgical robot does not have powerful sensory feedback function,and doctors cannot intuitively obtain the interaction force information between the surgical instrument and the patient's diseased organs and tissues during the implementation of minimally invasive surgery,which restricts the further development of minimally invasive surgical robot technology.In order to enable doctors to obtain intuitive force perception information and avoid potential safety hazards in minimally invasive surgery,it is of great significance to study force control technology of minimally invasive surgical robot.Aiming at the lack of force feedback function of minimally invasive surgical robot,a prototype of surgical robot from the hand end was built.The flexible force-sensing sensor and sensor pressure signal data acquisition system based on graphene are designed.The control system of microinstrument clamp force of surgical robot is designed,including hardware design of control system and upper computer software design based on Labview graphical programming language.Secondly,the forward kinematics modeling and solution of the surgical robot from the manual arm are carried out,and the simulation is verified in the toolbox of MATLAB robot.Particle swarm optimization(PSO)algorithm is used to solve the optimal inverse solution of the surgical robot.On the basis of kinematics analysis,workspace analysis and terminal manipulator trajectory planning are carried out for the manipulator,which provides a theoretical basis for the subsequent surgical robot to carry out surgical experiments from the hand prototype.The dynamic model of the surgical robot is established,which provides the control object for the research of the control algorithm.Then,based on the impedance control algorithm and the fuzzy PID control algorithm,the control simulation analysis of the microinstrument clamp was carried out.The impedance controller is designed based on the dynamic model of micro-instrument clamp.The simulation results show that the control algorithm has high control accuracy,small position error and fast response speed,and can achieve better force/position control effect.The fuzzy PID controller is designed based on the mathematical model of micro-instrument clamp single-joint motor.The simulation results show that the fuzzy PID control algorithm has better control performance than traditional PID control with small overshoot and high control precision.Finally,the experimental platform of hand prototype of minimally invasive surgical robot is built.The data acquisition and pressure calibration experiments based on the new graphene flexible force sensor are designed.The experimental results show that the sensor has higher precision,better sensitivity and better force detection performance than the existing sensor.The control experiment of microinstrument clamp force is designed.The experiment verifies that the microinstrument control system can realize accurate force control.